아래코드는 polygon을 이용해서 다각형을 그리는 코드인데요

저걸 마우스로 다각형을 그리는 방법점 알려주세요.

직선을 그리면서 다각형을 그리는 방법으로요?
<!--CodeS-->
LRESULT CALLBACK WndProc(HWND hWnd,UINT iMessage,WPARAM wParam,LPARAM lParam)
{
        PAINTSTRUCT ps;
        HDC hdc;
        static int nCount, nX, nY;
        POINT pts[]={
                {60,10},{160,10},{210,60},{210,160},{160,210},
                {60,210},{10,160},{10,60},{60,10}
        };
        switch(iMessage)
        {
                case WM_PAINT:
                hdc=BeginPaint(hWnd, &ps);
                SelectObject(hdc,GetStockObject(LTGRAY_BRUSH));
                Polygon(hdc, pts, 9);
                EndPaint(hWnd, &ps);
                return 0;
        case WM_DESTROY:
                PostQuitMessage(0);
                return 0;
        }
        return(DefWindowProc(hWnd,iMessage,wParam,lParam));
}
<!--CodeE-->